Spectacled Porpoise (Phocoena dioptrica)

The spectacled porpoise gets its name from the dark circle surrounding its eyes. Little is known about this porpoise, and most knowledge has been collected from stranded animals. Despite the fact that the species is not often sighted at sea, biologists believe it to be more abundant than what is suggested. The markings of the robust body are very distinct, the top half is black and the bottom half is white. The dorsal fin is quite large and rounded and the length ranges from 1.3m-2.2m. Most sigthings are from the southern Atlantic coast of South America but confusingely enough, some records are from offshore islands which suggests that the species is curcumpolar in sub-Antarctic and low Antarctic waters. It has been seen off the cost of Brazil, the Falkland Islands, South Georgia, Auckland, Tasmania, south Australia, Heard Island and Kerguelen. The animal has rarely been observed in the open sea.

South Asian River Dolphin (Platanista)

Since the 1970’s and until 1998 the South Asian River Dolphin was considered to be two separate species, the Indus River Dolphin (Platanista gangetica minor), and the Ganges River Dolphin (Platanista gangetica gangetica). This was due to differences in skull structure, vertebrae and lipid composition.
However, in 1998 the classification changed and they are now considered the only two subspecies of the genus Platanista. Externally, the two subspecies look identical, but they are geographically separated around the great rivers that have given them their names.
Among all cetaceans, the South Asian River Dolphin is the only one lacking a crystalline eye lens, thus making it blind. Instead, the species find food using echolocation. 
Uniquely among cetaceans, the South Asian River Dolphin swim on one side, usually by leaning to the right and cruising near the bottom of the river.

Northern Bottlenose whale (Hyperoodon ampullatus)

The northern bottlenose whale’s appearance is quite distinct due to its bulbous forehead. This whale is very inquisitive and frequently approaches boats; this, in combination with the fact that they tend to stay with wounded companions, made them easy targets for whalers, who in 1850-1973 killed tens of thousands of individuals. The northern bottlenose whale is found in deep waters of the north Atlantic ocean where dives of up to two hours have been observed.

Common dolphin (Delphinus delphis)

There are two recognized species of the common dolphin, the short-beaked and the long-beaked. The appearance varies so much that more than 20 different species have been suggested. Common dolphins are easily recognized by a distinct hourglass pattern on each side of the body, and the species is sometimes referred to as the hourglass dolphin. The common dolphin is often found in large schools of hundreds and even thousands of individuals. It is a very active dolphin, and frequently porpoises, bow-rides, flipper-slaps, somersaults, lobtails and breaches.

Franciscana (Pontoporia blainvillei)

The Franciscana (also known as the La Plata dolphin) is the only river dolphin which lives in the sea and saltwater estuaries. It prefers shallow coastal waters and is found along the South American east coast, from Doce River in Brazil to Bahía Blanca i Argentina. In proportion to its body size (which is fairly small, only up to 1,7m) the Franciscana has the longest beak of any cetacean.

Sei Whale (Balaenoptera borealis)

The Sei whale is the third largest of the rorqual whales, second only to the Blue whale and the Fin whale, and growing up to a length of 20m(66ft). Over short distances, the Sei whale can reach speeds of up to 50km/h, making it one of the fastest cetaceans. It is named after the Norwegian word for “pollock”, a fish found off the Norwegian coast around the same time of the year as the Sei whale. It does not feed on pollock, but consumes primarily copepods, krill and other zooplankton.

Haviside’s Dolphin (Cephalorhynchus heavisidii)

Haviside’s dolphin is small dolphin which is found solely off the coast of Namibia and the west coast of South Africa. Little is known about the species, although, much has been learnt about the behaviour of the dolphin in recent years.  It is very active at the surface and often approaches boats to wake- or bow-ride. It breaches frequently, somersaults and may porpoise at high speed.

Irrawaddy Dolphin (Orcaella brevirostris)

The Irrawaddy dolphin is a euryhaline species, meaning it can to adapt to a wide range of salinities, sweet as well as salt water. It is found in shallow coastal waters of the tropical Indo-Pacific and in large river systems such as Brahmaputra, Ganges, Mekong, Mahakam and Irrawaddy. Only a few years ago, in 2005, a second species in its genus was recognised, The Australian Snubfin dolphin which is found at the coastlines of northern Australia. The Irrawaddy dolphin’s appearance is similar to the Beluga, but it is most closely related to the Orca.

Vaquita (Phocoena sinus)

The Vaquita is a porpoise and probably the smallest of all cetaceans, reaching a length of 1,2-1.5m (4-5ft). It lives solely in the northern part of the Gulf of California and the population is estimated to around 100-300 individuals, sadly on the brink of extinction. It is probably the most endangered marine mammal in the world and is considered to be evolutionary extinct and globally endangered (EDGE). Vaquitas are mostly solitary, but have been observed in smaller groups of up to ten individuals.

Pygmy Killer Whale (Feresa attenuata)

Little is known about the Pygmy killer whale, since it usually avoids boats and human contact. It shares some similarities with the Orca, thereof its name. The Pygmy killer whale however, is nowhere near the size of a grown Orca (9,8m) and is in fact closer in size to many dolphins, growing up to 2,6m (8 ½ft). In captivity, some of these whales have behaved aggressively towards both people as well as other cetaceans and in the wild the Pygmy killer whales have been observed killing and eating dolphins. They are usually seen in groups of 10 to 30, and sometimes in even larger numbers.